Because of many advantages of light weight, antirust, broad degree of freedom for design, etc., in recent years, plastics are used extensively as materials for automotive parts, electrical parts, building materials, etc. Above all, because of low price and many excellent properties such as moldability, chemical resistance, heat resistance, water resistance, good electrical characteristics, polyolefinic resins are used in a wide range as industrial materials and the growth of demand is also expected in future. Different from synthetic resins with polarity, however, polyolefinic resin is nonpolar and crystalline, hence it has also a drawback of difficult adhesion with it.
For this reason, as a pretreatment for painting and adhesion, method of providing plasma treatment or gas flame treatment onto the surface of moldings to activate, or method of painting primer (undercoating agent) having chlorinated polyolefin as a major component is adopted.
For the painting of polypropylene bumper of automobiles, for example, primer compositions having chlorinated modified polyolefin as a major component are disclosed in Japanese Unexamined Patent Publication No. Sho 57-36128 and Japanese Patent Publication No. Sho 63-36624.
With these primers comprising chlorinated products, the adherence onto polyolefin having been produced hitherto is excellent, but, it is the present situation that, with the advent of high-modularization of prime material and low-temperature baking in recent years, prime materials that give insufficient adherence are seen, making it impossible to correspond sufficiently with conventional chlorinated polyolefinic resins.
Furthermore, it is the present situation that the chlorinated polyolefinic resins exhibit relatively excellent adherence onto polypropylene prime material, but the adherence is insufficient onto other prime materials (poly(vinyl chloride), polycarbonate, PET, ABS and nylon).
The chlorinated polyolefin resins etc. having been proposed hitherto were those having chlorinated isotactic polypropylene (hereinafter IPP), wherein IPP produced by using Ziegler•Natta catalyst as a polymerization catalyst was chlorinated, as a major component.
Whereas, an adhesive that uses chlorinated syndiotactic polypropylene (hereinafter SPP), wherein SPP produced by using metallocene compound as a polymerization catalyst was chlorinated is disclosed (Japanese Patent No. 3045498 and Japanese Unexamined Patent Publication No. Hei 7-18016). However, this chlorinated SPP has more improved solvent solubility than that of conventional chlorinated IPP produced by using Ziegler-Natta catalyst as a polymerization catalyst, but it exhibited excellent adherence only when the prime material is polypropylene and it has a drawback of insufficient adherence onto other prime materials (poly(vinyl chloride), polycarbonate, PET, ABS and nylon).
The purpose of the invention is to provide a binder resin composition with good adherence and gasohol resistance to various polyolefins including polypropylene prime material, poly(vinyl chloride), polycarbonate, PET, ABS and nylon prime materials and also with excellent solvent solubility.